The present disclosure herein relates to optical devices and methods of fabricating the same, and more particularly, to optical devices in which an optical active chip such as a laser diode and a photodiode and a planar lightwave circuit platform having an integrated light waveguide are hybrid-coupled and methods of fabricating the same.
In an optical network for high-speedily and effectively transmitting a large amount of data, it is necessary that an optical active device performing light source, optical detection, and optical amplification functions and a light waveguide in which optical wavelength division and optical multiplexing are possible are integrated to realize an optical transceiver and optical amplification module at a low price.
Such integration technologies are divided into a monolithic integration technology in which an optical active device and a light waveguide are realized and integrated using an optical semiconductor that is a single material and a planar lightwave circuit (PLC) hybrid integration technology in which an optical active device and a PLC platform are integrated using a flip-chip (F/C) bonding.
In the monolithic integration technology, when each of optical devices is integrated on a single substrate, it may be difficult to realize an optical transceiver module at a low price due to limitations in optimization of the optical devices, reproducibility, and productivity. On the other hand, in the PLC hybrid integration technology, an optical active device having optimal performances may be hybrid-integrated with a PLC platform having a light waveguide function and a wavelength division multiplexing (WDM) filter function to improve productivity. Thus, the PLC hybrid integration technology is considered as a core technology that may realize the optical transceiver and optical amplification module at a low price.
A PLC platform may be easily manufactured using existing light waveguide manufacturing technologies and platform post-processes such as an etching process and a metal deposition process. Thus, since optical coupling efficiency between a semiconductor chip that is an optical active device and the PLC platform including an integrated light waveguide affects performances of a hybrid integrated device, it is necessary to devise and establish an F/C bonding structure and method, which may improve alignment accuracy therebetween.